Sixteen Natural Droughts Since 1658 Worse Than Todays

Tree rings are magical. Not only can you reconstruct temperatures from the past, but you can reconstruct droughts (rainfall).

Whenever I see the word “novel approach” I worry we are in for BS.

However, since the authors of this paper are saying things were worse in the past than present I like to pretend I believe them.

They also sort of say that more dendrohydrologists are needed. Surprise.

Recent streamflow droughts in south coastal British Columbia have had major socioeconomic and ecological impacts. Increasing drought severity under projected climate change poses serious water management challenges, particularly in the small coastal watersheds that serve as primary water sources for most communities in the region. A 332-year dendrohydrological record of regionalized mean summer streamflow for four watersheds is analyzed to place recent drought magnitudes in a long-term perspective.

We present a novel approach for optimizing tree-ring based reconstructions in small watersheds in temperate environments, combining winter snow depth and summer drought sensitive proxies as model predictors. The reconstruction model, estimated by regression of observed flows on Tsuga mertensiana ring-width variables and a tree-ring derived paleorecord of the Palmer Drought Severity Index, explains 64% of the regionalized streamflow variance.

The model is particularly accurate at estimating lowest flow events, and provides the strongest annually resolved paleohydrological record in British Columbia. The extended record suggests that since 1658 sixteen natural droughts have occurred that were more extreme than any within the instrumental period. Flow-duration curves show more severe worst-case scenario droughts and a higher probability of those droughts in the long-term reconstruction than in the hydrometric data.

Such curves also highlight the value of dendrohydrology for probabilistic drought assessment. Our results suggest current water management strategies based on worst-case scenarios from historical gauge data likely underestimate the potential magnitudes of natural droughts. If the low-flow magnitudes anticipated under climate change co-occur with lowest possible natural flows, streamflow drought severities in small watersheds in south coastal British Columbia could exceed any of those experienced in the past ∼350 years.

 

10 MORE Random Canadian Tmax from 1980

A few days I published 10 more randomly chosen graphs of TMAX using Environment Canada’s monthly summaries.

I was fiddling with the graphing code to add the overall rate of temp change and color the title – red for warming and blue for cooling.

I took a closer look at 3 stations (2 are airports).

Tmax temperatures falling at -.414C /dec, -.224/dec and -.246/dec

April Tmax in Brandon have fallen 7C in 35 years.

Tx - SWIFT CURRENT CDA SK . 1980 to 2015 . -0.414 C per decade

Tx - FORT MCMURRAY A AB . 1980 to 2015 . -0.224 C per decade

Tx - BRANDON A MB . 1980 to 2015 . -0.246 C per decade

 

 

 

 

 

 

 

 

 

10 MORE Random Canadian Tmax from 1980

A few days I published 10 randomly chosen graphs of TMAX using Environment Canada’s monthly summaries.

I picked 1980 to 2015 partly to create a round number and partly because that is sort of when AGW became noticeable.

I picked TMAX because I think TMIN’s are rising because of UHI.

The red lines indicate a warming trend. The blue a cooling trend.

Anyone see evidence of CO2 making it warm?

Here are 10 more.

Tx - BONILLA ISLAND BC - 1980 to 2015

Tx - CASTLEGAR A BC - 1980 to 2015

Tx - BRANDON A MB - 1980 to 2015

Tx - GOLDEN A BC - 1980 to 2015

Tx - KANANASKIS POCATERRA AB - 1980 to 2015

Tx - MICA DAM BC - 1980 to 2015

Tx - SWIFT CURRENT CDA SK - 1980 to 2015

Tx - FORT MCMURRAY A AB - 1980 to 2015

Tx - VANCOUVER HARBOUR CS BC - 1980 to 2015

Tx - BONILLA ISLAND BC

10 Random Canadian Tmax from 1980

Every once in a while I visit the data for the Canada. Earlier today I looked at the station nearest me (NANAIMO A).

But since I have the code … I thought why not look at 10 random stations that have data in 1980 and 2015.

Today I am looking at TMAX monthly data (using Environment Canada monthly summaries) for 10 random stations from 1980.

Each line of graphs is a season  – Dec/Jan/Feb …. etc.

 

Tx Average BEAUCEVILLE QC

 

Tx Average NEW GLASGOW ON

 

 

Tx Average TERRACE A BC

 

Tx Average WHITECOURT A AB

 

Tx Average AROOSTOOK NB

 

Tx Average BARWICK ON

 

Tx Average MIDLAND WATER POLLUTION CONTROL PLANT ON

 

Tx Average QUALICUM R FISH RESEARCH BC

 

Tx Average UCLUELET KENNEDY CAMP BC

 

Tx Average GIBSONS GOWER POINT BC

 

Nanaimo Tmax from 1980

Every once in a while I visit the data for the weather station closest to my hometown on the west coast of Canada.

Today I am looking at TMAX monthly data (using Environment Canada monthly summaries) for NANAIMO A from 1980.

Each line of graphs is a season  – Dec/Jan/Feb …. etc.

5 months are warming. 4 are cooling. 3 are cooling ever so slightly.

If there is a CO2 signal in there I am missing it.

Tx Average NANAIMO A

 

Nanaimo BC Temperature Range

I live near Nanaimo BC (data from 1947 at “NANAIMO A”). I was curious what the temperature range for any given day would be.

By temperature range I mean find the warmest it has ever been for a particular day and then subtract the coldest it has ever been.

December 1st , February 4th, November 14th and May 16 have the biggest range = 32.8C.

November 18th has the lowest range = 16.9C. (I find it interesting it has never been colder than -4.4C on November 18 when it has been -16.1C on November 14th.

(Remember this when someone says humans and animals will notice a 1C change in the next 100 years).

Top 10 and bottom 10 below.

Biggest Difference:

Month Day Min Max Difference
12 1 -18.9 13.9 32.8
2 4 -16.7 16.1 32.8
11 14 -16.1 16.7 32.8
5 16 -4.4 28.4 32.8
6 17 0.6 33.3 32.7
5 29 1.7 34.3 32.6
5 12 0 32.4 32.4
5 28 0.6 33 32.4
5 14 -0.6 31.7 32.3
12 24 -13.9 18.2 32.1

Lowest Difference:

Month Day Min Max Diffference
11 18 -4.1 12.8 16.9
3 15 -3.3 14.5 17.8
12 5 -7.1 12.1 19.2
11 10 -4.4 14.9 19.3
12 11 -6.1 13.5 19.6
12 3 -5.9 14 19.9
12 12 -6.3 13.9 20.2
2 23 -5.6 14.6 20.2
3 14 -3.9 16.6 20.5
3 17 -5 15.7 20.7

Nanaimo Tmax from 1947 to 2015

Every once in a while I visit the data for the weather station closest to my hometown on the west coast of Canada.

Today I am looking at daily TMAX data  from Nanaimo Airport (1947 – 2015).

1987 was the warmest year (1958 was 2nd warmest FYI) . 1955 was the coldest They are shown as the orange and blue lines.

Here I have graphed all the available data in the style I usually use for Sea Ice data.

2015 is in red. There are gaps because Environment Canada doesn’t seem to care.

Notice that temps can fluctuate by 20C for the same day in different years.

Ponder this … why can we humans (and crops and animals)  adapt to 20C swings but we can’t adapt to a 1C change over 100 years?

Click graph for larger.

NANAIMO_MAXTEMP_Antarctic_Style

Update: I added Tmin
NANAIMO_MINTEMP_Antarctic_Style